Association of COVID-19 Vaccinations With Intensive Care Unit Admissions and Outcome of Critically Ill Patients With COVID-19 Pneumonia in Lombardy, Italy
Authors: Giacomo Grasselli, Alberto Zanella, Eleonora Carlesso, Gaetano Florio, Arif Canakoglu, Giacomo Bellani, Nicola Bottino, Luca Cabrini, Gian Paolo Castelli, Emanuele Catena, Maurizio Cecconi, Danilo Cereda, Davide Chiumello, Andrea Forastieri, Giuseppe Foti, Marco Gemma, Riccardo Giudici, Lorenzo Grazioli, Andrea Lombardo, Ferdinando Luca Lorini, Fabiana Madotto, Alberto Mantovani, Giovanni Mistraletti, Francesco Mojoli, Silvia Mongodi, Gianpaola Monti, Stefano Muttini, Simone Piva, Alessandro Protti, Frank Rasulo, Anna Mara Scandroglio, Paolo Severgnini, Enrico Storti, Roberto Fumagalli, Antonio Pesenti, Roberto Keim, Federica Vagginelli, Antonello Sala, Guido Merli, Patrizia Ruggeri, Giorgio Villani, Mario Riccio, Elena Zoia, Antonio Castelli, Riccardo Colombo, Roberto Rech, Paolo Gnesin, Davide Coppini, Nicola Petrucci, Benvenuto Antonini, Luca Landolfi, Fernando Arnaiz, Clarissa Forlini, Flavia Stefanini, Antonio Micucci, Jlenia Alessia Marelli, Francesco Torresani, Cristina Panzeri, Elena Paolini, Davide Guzzon, Laura Maderna, Gianluca Russo, Angela Berselli, Alberto Biondo, Claudio Montalto, Leonardo Bianciardi, Federica Della Mura, Giovanni Marino, Massimo Zambon, Matteo Subert, Giuseppe Citerio, Maurizio Saini, Roberto Rona, Angelo Pezzi, Giovanni Sabbatini, Silvia Paganini, Virginia Porta, Alberto Benigni, Ezio Bonanomi, Fabrizio Fabretti, Paolo Gritti, Giorgio Arachi, Maurizio Raimondi, Alberto Casazza, Gianluca De Filippi, Francesca Piccoli, Michele Umbrello, Silvia Coppola, Tommaso Pozzi, Alberto Corona, Emanuele Bossi, Stefano Greco, Alessandra Besozzi, Remo Daniel Covello, Mauro Della Morte, Fabio Sangalli, Dario Gasberti, Davide Maraggia, Alessandro Motta, Emiliano Agosteo, Lucia Crottogini, Olivia Leoni, Marcello Tirani, Marco Carbonara, Stefania Crotti, Chiara Fusaris, Paolo Properzi, Nicola Rossi, Paola Tagliabue, Daniela Tubiolo, Giuseppe Maggio, Michele Pagani, Fabio Sciutti, Michele Bertelli, Carmine Rocco Militano, Alessandro Morandi, Roberto Valsecchi, Giovanni Albano, Enrico Barbara, Andrea Ballotta, Elena Costantini, Massimiliano Greco, Paolo Perazzo, Roberto Ceriani, Marco Ranucci, Marco Resta, Maria Rosa Calvi, Sergio Colombo, Antonio Dell'Acqua, Francesco Marino, Pietro Sebastiano, Giuseppe Sala, Nicolangela Belgiorno, Rinaldo Cosio, Luca Guatteri, Uberto Viola, Marco Galletti, Vincenzo Primerano, Enrico Visetti, Matteo Giacomini, Armando Alborghetti, Alberto Bertazzoli, Michele Bertoni, Tommaso Mauri, Giada Prato, Nino Stocchetti, Luigi Vivona, Giulia Waccher, Matteo Filippini, Nicola Latronico, Marco Giani, Matteo Pozzi
Journal: JAMA Network Open (2022)

Importance Data on the association of COVID-19 vaccination with intensive care unit (ICU) admission and outcomes of patients with SARS-CoV-2–related pneumonia are scarce. Objective To evaluate whether COVID-19 vaccination is associated with preventing ICU admission for COVID-19 pneumonia and to compare baseline characteristics and outcomes of vaccinated and unvaccinated patients admitted to an ICU. Design, Setting, and Participants This retrospective cohort study on regional data sets reports: (1) daily number of administered vaccines and (2) data of all consecutive patients admitted to an ICU in Lombardy, Italy, from August 1 to December 15, 2021 (Delta variant predominant). Vaccinated patients received either mRNA vaccines (BNT162b2 or mRNA-1273) or adenoviral vector vaccines (ChAdOx1-S or Ad26.COV2). Incident rate ratios (IRRs) were computed from August 1, 2021, to January 31, 2022; ICU and baseline characteristics and outcomes of vaccinated and unvaccinated patients admitted to an ICU were analyzed from August 1 to December 15, 2021. Exposures COVID-19 vaccination status (no vaccination, mRNA vaccine, adenoviral vector vaccine). Main Outcomes and Measures The incidence IRR of ICU admission was evaluated, comparing vaccinated people with unvaccinated, adjusted for age and sex. The baseline characteristics at ICU admission of vaccinated and unvaccinated patients were investigated. The association between vaccination status at ICU admission and mortality at ICU and hospital discharge were also studied, adjusting for possible confounders. Results Among the 10 107 674 inhabitants of Lombardy, Italy, at the time of this study, the median [IQR] age was 48 [28-64] years and 5 154 914 (51.0%) were female. Of the 7 863 417 individuals who were vaccinated (median [IQR] age: 53 [33-68] years; 4 010 343 [51.4%] female), 6 251 417 (79.5%) received an mRNA vaccine, 550 439 (7.0%) received an adenoviral vector vaccine, and 1 061 561 (13.5%) received a mix of vaccines and 4 497 875 (57.2%) were boosted. Compared with unvaccinated people, IRR of individuals who received an mRNA vaccine within 120 days from the last dose was 0.03 (95% CI, 0.03-0.04; P &amp;amp;lt; .001), whereas IRR of individuals who received an adenoviral vector vaccine after 120 days was 0.21 (95% CI, 0.19-0.24; P &amp;amp;lt; .001). There were 553 patients admitted to an ICU for COVID-19 pneumonia during the study period: 139 patients (25.1%) were vaccinated and 414 (74.9%) were unvaccinated. Compared with unvaccinated patients, vaccinated patients were older (median [IQR]: 72 [66-76] vs 60 [51-69] years; P &amp;amp;lt; .001), primarily male individuals (110 patients [79.1%] vs 252 patients [60.9%]; P &amp;amp;lt; .001), with more comorbidities (median [IQR]: 2 [1-3] vs 0 [0-1] comorbidities; P &amp;amp;lt; .001) and had higher ratio of arterial partial pressure of oxygen (Pa o 2 ) and fraction of inspiratory oxygen (FiO 2 ) at ICU admission (median [IQR]: 138 [100-180] vs 120 [90-158] mm Hg; P = .007). Factors associated with ICU and hospital mortality were higher age, premorbid heart disease, lower Pa o 2 /FiO 2 at ICU admission, and female sex (this factor only for ICU mortality). ICU and hospital mortality were similar between vaccinated and unvaccinated patients. Conclusions and Relevance In this cohort study, mRNA and adenoviral vector vaccines were associated with significantly lower risk of ICU admission for COVID-19 pneumonia. ICU and hospital mortality were not associated with vaccinated status. These findings suggest a substantial reduction of the risk of developing COVID-19–related severe acute respiratory failure requiring ICU admission among vaccinated people.